SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'ff48f81d43379098e02d3583955385967329cb0bcc8adac8450496aa84715372' 
  AND token = 'smFMfT3No0fIqsc+cjEysewyXS6X29T1ytO95PTyTsc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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