SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'b893934fafe331a542a82a2ff5fc5364b2503e7796445df04fc55e67ab8c1661' 
  AND token = 'RqBupaXt/vKo8gI+A3l5uOBBklmIL37cl4zLhMAak/Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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