SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'edb986e8d944afe2002c91a030779648c41be3c52ed266d6808e0d4b40f088cc' 
  AND token = 'Bm1IkyUndUvmg9bAYWr386/wntEyhYcEG7NHv7hbr84=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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