SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '43159cde209413062c1b85151a913607f363c3a22266f5a62af94297fd71fe65' 
  AND token = 'AsO1wB4vvTQOvHGwh4iBs8/c1NldXhos4t1uoUotCgs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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