SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3140f3e1ff4447cc77b9d96376280d7787d4b66b00bf982606c6432e38d66121' 
  AND token = '2d6yiv5J/jXWgrWF+VGxknLxJ5hRmZP2EfpxH+DPDEo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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