SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '264144b6eba0e24425021f979ee5360a07c65c2a45c206b890726cdfc403b281' 
  AND token = 'unSc0KMFt0ydQyjF7juqHtiDZwae++evOGFiNoiio5o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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