SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bae6775f32f310c20db753419307342454794ad6a5e897af9c4557a47436e6f2' 
  AND token = 'lexq8CbH/9WLkYWLhWIZqOzN/sz2EtYI42ell+juvPQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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