SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '40df804d47eb11be0dbab39f92707ec71df6b73fbf120ecc638502e816787236' 
  AND token = 'skuVdCp/MjW+gb8GqNKOapzuWFpZlVBB2kBY1BZEK5k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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