SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b6ce24da57f090a9f56e5f724ee4d68625240ed188f4fde476de1727af2c5b71' 
  AND token = 'sZPX1/lan4isQXCuPgcy9kljkN0nX3AobKm54Pkq70I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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