SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'df56f79e8f266721b5f53b34fd5f1eda4f607d27d75b0a1754980dc415bb3b78' 
  AND token = 'uBmXFmMCPCKYpzleKIBeAD1JK+stDx43PofVcwxx7F0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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