SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7645b52da6135411cf9d0f46a6c1e346c9bb88b7562a1d902bbc3bd38c1a96f4' 
  AND token = 'g0VyDIpco62sRskp18ZuSlWOk7r/MVgvzj/fJTUHAIY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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