SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '54551b28df3e898295b7dd56727c10caf13ffbf9354c07031295c1fd5121aacd' 
  AND token = 'LUq83YuK7Xg7A+v0QahjnkoYWGifoZZVVMIq8lIuyak=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00059

JSON explain

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