SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cbb97cb72fbc604149df625bfb8ff0979bb667a056c098af7cf4e3a17b4a92ae' 
  AND token = '1HBczsmWUKZofhUuxpefZy3zJoBV51OOLqlNIXwWmSQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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