SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '05e15c22ffdc42fd3721f485ad6ed725add29900c0d96d986acaabc8cdcb6698' 
  AND token = 'p1SRDPMUB+AL6xiX2BhIRcAbAb18vRdqtiIaL1Nnnr4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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