SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'dc08444c467324c99b45ccc810e5701f9b5b342749c835d2a847e2df24153565' 
  AND token = '35lI0s8Abufce4xtTEnbo3IGH5lY+uKWjG/mItHk8HU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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