SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '8f3a0db92214245120d02b1d1a85008dccc89a5864d776aadf0758e6d811321e' 
  AND token = 'ViyMA2e2VJs8IfEcQOm7qAroQQ3EjKzc+qKgukQGb/U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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