SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '7d0bfb651373ce4b6ef0732b514fc757bb24d2b44415e4cf96a77b2e0af83528' 
  AND token = 'c9d+JGGKw536C1UDKxMyY0AY/kno0PuyTgXyg6uOcIA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00124

JSON explain

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