SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '14d946f90657631e92a9d8ff4e9a3099ac6d3cf1fad662fb1a54730f11de4ece' 
  AND token = '3/mXc/tdrFjEmX9NHpDNdjmG6CGFZg7aYcum1QN5I8I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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