SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b052f152cee062b8279c07a840cafba90de693d1472e782e5dc7efb2644d92c0' 
  AND token = '0SpOP8UgRFCEWIouQJVzC45BOYdWBxpVJshjG7ZUMrg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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