SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '3803c5cd04ed9112bda879c494032c80d7235cbb815646a4f94b913fad25fb21' 
  AND token = 'rfkZNgtnJaZi94Z61ir+zQdVBZoqIu/vVRNQk9MCL3Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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