SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a7bff5defe120f0c5f423d0cd9f1a27ea337dc72bd1b90507f8e77cad90fe55' 
  AND token = 'K+K4gUYwGJgZCljPrqYQJZ3KBIYM0Wcv2HZrOMoCkHA=' 
  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"
    }
  }
}