SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dea76851682e0283ab0d4a0296525f913081f91c59a95e8d37677e7774d1ae7a' 
  AND token = 'GGd+nVmIYRC/z4dmvdqxuxHdkFffXpmBDDd4UGR/YJs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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