SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff20020c0644badc8ba58c7eefe7ffbf66a6f17c3d1607bd394f09afc50734df' 
  AND token = 'vZHCZWGNweoD7heFziGe5gYQRuRyEvV4hBUg3X2fFy8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}