SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '28941d3d1aad225b1eeaab89b5c721f57340585116a21b6b6efe756df7c55565' 
  AND token = 'p+OtskNWcJYgizfaLgL7mYnKR/MxItpT15AkRzz3/IA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}