SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '66e50f14987bddba8fe1703b92458abc30e86b7dab798d0484177a852b304c66' 
  AND token = 'F78fjazDesRCwJ0GJc/Ab+ZhK2eLIYhrqjLenXVXTmU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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