SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '74504f6e0ac36b6186ffe1b20223dbfbe2124583569da1f327463e5e9c97f8c3' 
  AND token = 'JdiuDIogPLkDmya5jc3Y4Rv7bFXIzJ4TaDacM/F35gw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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