SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '2ad1b038742f738e59d65681be9060289802a85346cbb1a19041b47a72844fc5' 
  AND token = 'KOlYHR+mS0PNuUf3qPMG1nNCKOMnir7oS5nah0s7eJM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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