SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c845491412010d796bc851e7423c8c7dde1e4d5d2dfb7b6cd9d5b9afe85b63da' 
  AND token = 'S2ZurLPwxOQW3vOaYjlJkGBagddyHaZZDBV+ynsKGpI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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