SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '188aa9850aa7dd3706a5a531f217107d1358f7585633323f635758ca6abf5d21' 
  AND token = '4Na4Pq1RvIkytcijylgKV3eidieiFG5f3YQQFAx1Vio=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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