SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '39b3619557f84424035e786d207c1900bc2f45fa68bb9825c8ca5326c1058eef' 
  AND token = 'iewPRhS5g9dF8LfpuIkyno+Pa9POkV37390HMbsp+9I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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