SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b816566c00aada824f0b1f6188ea1bf58ffadb25236d244f2d5fed1f1d38b6ee' 
  AND token = 'l8qcvIQVR6I3P+yiKeRwVUtONrHwSsNHYKasb8XPPyM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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