SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '87e778718dc62724f7571ea525e829b5321dc2c906293886416262b78c0a9c4a' 
  AND token = 'DcDjmWbHmRxe/ZeVCAUHQkGAXaIkMEqc0O+2lJSmXyg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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