SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6a212cf77f790cd0a44bc9d6b8765b440399fa5dd10f2b999a93d5811101e222' 
  AND token = 'CknkGTYqH4GcxrybEXDejHF+6qgYuN3zYg7rneonny0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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