SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '9473ce22d2a202e3dc625068709116d98154f315062612bec81a1250ac466b0e' 
  AND token = 'pBkvBW7X+B1VmWgbKyXipIHVC/YBJflnfOIEG3Eo3wM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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