SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7128c830753f9e65d7bcfa2894f03395e844a78bd72663231762b1c7f171ad5a' 
  AND token = 'NJ9AVtsxjJpaSzB94fSzP1FwIxOzrIKWg9kmwVNX1PE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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