SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '73bdf6e81565ac1b754f7a5b905790604b31da9b0afc3bbf91166400aa6b8714' 
  AND token = 'D5lSExUasy83RtADDTzhy6RgJ14uVlksg7rm3+sODRk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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