SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4ba915909542109c4283c1f203ff5cb224ae1abdf935d88235e998da820e1946' 
  AND token = '5hPgy9klmcHei7GGJb6GeUN3zomPG9quY04ZNSu9XXM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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