SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '206fa79d363d384b92099b92c1b941eda733b63d328283e413289e1e15f25321' 
  AND token = 'bv5RlUHiNVjrJDr5rO2vukmkbvlAiLB2zy2T8P+qWI8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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