SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a7a2a2f3617964d1296b4d837c55b8c7751474da0062eb19155e77e887c69259' 
  AND token = 'gsd+sIN6b4Uay8QMoCzqGVvisPYThSznegTjCZPtp2o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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