SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8fc9e31544e8fcb98463265cb0b4470ef8bfb822e0463bf83877b34707c3bc76' 
  AND token = 'cXvOwbZY/Lro2kZzMWwvMoz4iF51+uYVqJAjQHU0TEY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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