SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ae8635c1d67625bafd144b15e31defa65de50c2dfac24befcff92b95db0fe81a' 
  AND token = '0OIPvgHdAihiv/Iqq1wIs2ZSTOh/O9ib12IB0ekxXlw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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