SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '71621fc192aae4371174f3055c4a9742a87b800fd7b719c0e466188ad65faed2' 
  AND token = '+twPNAraA6iuPAVRKX+F8zWVZwGFgo3y0sUPH7/zK2I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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