SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f051a12a3b80738f7c57471510c118bc3de2fba8ecbc9d43637f9a8c211476c9' 
  AND token = 'xC1qNLVXACpNN1yIjJjDP/AOHFDK4nbZK+ipylsYY0M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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