SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5d81869fc239579698e6f3e401e3d75fc2082684201f7d177d8ea98113602a1a' 
  AND token = 'sPLyQRbS14rjKXQXNxR63GrJnhWgYfrrqRaqcX9WvfI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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