SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84061f1ed3bee79818abffe4dfb198a32aa6b99d00c68b1c2cc5c334def46343' 
  AND token = 'pTSQY//RhcHsHa8LteyHpBeUgatI9nqb/RzHK+gSErM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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