SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'fb5be37cff309f9a80bad1048d8af9ef2cb683e0a63ae3e9e1d5d760fbbdb03b' 
  AND token = 'DgpZboMGzdArV+Z9pHnW9dEMTVEqymxgH//PmmQntUY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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