SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e5043f08dd9ae21f6a3bd40ec3ea8d022aa058aac87d7511a70b3c3ed0ecfd1a' 
  AND token = 'Y8nLgUxBNTs58+Dl5ZnAOPhXexcjW249GYO5omjwC8I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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