SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd69eac36e7170aa8a4ba9729b11949956f79a5cc19d4cedcd4d07d5e89903a25' 
  AND token = 'R/fUHyth99aji3aibYfFT4SCQk9DgPkJcdW10WyOb18=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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