SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '58d756c704559e6010a14fb3c5d0026f57b564191fdf88e723cc6f643288f6d7' 
  AND token = 'S8vTj+Eb/2k5HnELoflPLyEBEENVTKVF12vBDptXydw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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