SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '45e705e2cebcd85fa40c7fc88d1dffc4997e26399e3ec7e4d3853bc304def0d2' 
  AND token = 'vKhfpEmf1DCNLuG72Q2Bs2gkgLGVW/S5V1j4m1JCzbw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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