SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6344447b63cd8abd5856e6d3aeef62697414be2573e49b5f0cb12d428c0a78b9' 
  AND token = 'oBNQLEYnKmHFVlHFH1/SU/QD+3h+0y+lAPk5rl+wM1E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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