SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '89238e2c439318885927d21018dc740457007a607525511558bd5bab0bbfe09e' 
  AND token = '9h8/DzqVPh1sM/BTW2gtfCSfqtgu0OJPw6gxq5xL96s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00009

JSON explain

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