SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '11d3c2402566b52993bd10f3b06311a58462225c0a78f54ef19b9a4af99d3209' 
  AND token = 'f8/GQxpRCwVCc7YcOpbpEWs+ZPq9LdXyBnBGF6yr5cY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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