SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '76578fa075cf7cfc34f329521d89f6d3379f7af9abefe32918cc08c1983215bc' 
  AND token = 'pNPwoBgOoTx1SUjjG5g9n8WHDtMyuLSBpzMMwvbOD04=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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