SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd8e0ee72f5ac849849823a5082bef32023eedf890304d1f27bcfaee5a8aa1ef6' 
  AND token = '5qSKZfpDImHVry7V7ZuCt+Xmk0EisXVAYAzRoyTXLV0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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