SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b400d9cebe1245922e89cccb1bb6faa0c14e29c2f31e5e5f09babafc8eb3891f' 
  AND token = '84/mcNRLf0jN7koLSCpbcpWhRxm3UAs7pfm1T9I4pOk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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