SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3dc32400889facc32db3ce7594c200259acc52c8030049ae9b14a0bb7456939c' 
  AND token = 'bzriiybC9NyMeLYMdaH09VVc+LTCYVXQlINgvS27h9E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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