SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '99348e915f05114ec42a2b2c8e30dd256a09a192528a4f34671c174468fbe086' 
  AND token = 'H5YG3hP998x9/kWGljRQ/wlqMEMWfn7cyMT9k/u0VsU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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