SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a09fee45a1fa31b4b66d45aa423381adbf5a8b43834e49484f96537cf3fc53c7' 
  AND token = 'Q4HhZ8NnObiz240HDKejSgaqBzcxvF+raP4GJ3//vhs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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