SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a9bb627904357bd0e915fa632af45f02265db1529833b437ae87e7f05bf5e03a' 
  AND token = 'phPTy0L47uq25XN9IuRkOtqg9L4oLnJTLqI98nIstm4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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