SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '75e92944015c45334b2ed616c94007fc885ae1d38c8f6939dc784892a2dae8e6' 
  AND token = 'bSD8pGHoZqJqtneQf4+jsHJfx1/J0aQe0x/eZc+B9x8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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