SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd4ad324a504f58b366d10c8c07f4e9ec791b50bdfb27b9863fdbcd83d74ceae' 
  AND token = 'XYMml//WlfLLrlVQ0FieLnVoNpux+GATPf5axUN0KWI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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