SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '7926af3fdeb42448f386bb1bca1e571bb20656e6c53172e4a3d4fe5eb6e006a9' 
  AND token = 'mI/B0/jPt4INt1WiWAMG3KZDxTU7a5D1BVZ+katGPhw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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