SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '054990440f511129ca761645f31ce726e7bf0372780ec46142410a82a557e0b6' 
  AND token = 'pLQ6lz7LlIltgXW4VAvkUvhyzOfj7mhtVXt0SHwbfXA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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