SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bd6c9d6ba8882f12c5bb83e612b86a0b785ca0866631bc7aa2ee8e73c0a39b3e' 
  AND token = 'N/+XY2PCbtn1zbVZIAbFh3oV2MSJuTFtduQud5AStsQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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