SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '396ea94b3ac312b30b510de7b706053aff0ac5cde8bc36b11eb2b1c761fa1cc2' 
  AND token = 'IptRCqb15M4UNRd4R1cDeLJYeLvuuSWc0qIcA/wUBVo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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