SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e4322236ff6524465dd0bc0c1263bf681bafdec1e8865b04500edd427bc4c968' 
  AND token = 'bCtICOLFlmWpFeW0iIXzhJn0xWLyXRIVjTdCPOe8dH8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}