SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9942f8206ed84bde5ce4d9a3e960cb700ab479811fcad203622bf6d37cec598f' 
  AND token = 'lCfEhmcAtVOVqTbbVY5ST1AIZT5rxkRSucUtbJVnzxc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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