SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd426e8800bf720b20a954f002be374c717755a4b51d80d2fcc4a825736ef54a5' 
  AND token = 'oNCobMl9sIOPiMuXtoF4x7eFAXDNuhGISygLslSKaXU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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