SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a7b0263bed99a5a94f39f81de3aaa620961876cf0ab1636fc257aebf3e26b034' 
  AND token = 'uRBQE5hudliiF0WGxpax9Mg8IPTuD/0ojiSrJVGxT3k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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