SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '20ccc1816e853a1c3d6c85d1de54da9e1619007d52b9d8b72de46c3d60328439' 
  AND token = 'aUf8axP8V3ygt3vFvven2nB2calC5ChSHYx4I5oYzxY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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