SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f34721d11d16bb2aff6d1c90e8dae11a60fe72337357fa88dc26cfa96984177' 
  AND token = 'n/hH2jQkQBCVHlpa7sRCFCIW6lMsZ9gnkyRdDBVYFII=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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