SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '446ad9a1df267a41b59049149ef416997414fc024de57d2ce97fecf0334b5872' 
  AND token = 'yBihHdz3heg9BE34rYxt6uEDky5u4frLUl3HLhJmcmI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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