SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a28e4ece1c6fbc693441e04a7f79417437a3b8117376a9cf845506dc09c4b205' 
  AND token = 'c8IfUNPSXQlllgjbk/ygZNSi1oo/sEQFXGiXXIjNPIc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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