SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c7ac7998ea32d2db68233df49b21fc21c374746b6470b2d1eb048a775c9c17db' 
  AND token = 'H9KOGvJ9N01OYXoQzBu7LNWTUGqwEO8D4GveMlKnSU0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}