SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f0a75798eebfe6bbf924ab8c19342adaa9b562c4cab39f86a7cbd295f15c3ad0' 
  AND token = 'DV1iNhxqWxL2d0RYubAD0GYjRyKhfU+AqRzZrQ/r7pM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}